Spliced absolute time grating linear displacement sensor

Abstract

The invention discloses a spliced absolute time grating linear displacement sensor which comprises fixed rulers and a movable ruler, the fixed ruler comprises a fixed ruler base body, a coarse machine coupling unit and a fine machine coupling unit, the movable ruler comprises a movable ruler base body, an excitation unit, a coarse machine sensing unit and a fine machine sensing unit, the number of the fixed rulers is S, and the S fixed rulers are sequentially spliced end to end in the X direction to form a fixed ruler set. An alternating-current excitation electric signal is input into the excitation unit, and when the movable ruler moves in parallel in the measurement direction relative to the fixed ruler set, an absolute linear displacement value can be obtained after a standing wave signal output by the movable ruler is processed. Interference of various electromagnetic waves in the air can be reduced, wide-range absolute linear displacement measurement with the measurement range reaching several meters or even dozens of meters is achieved, the application range is wide, and sensitivity is high.

Description

Technical Field

[0001] The invention belongs to the field of precision measuring sensors, and in particular relates to a spliced ​​absolute time-grating linear displacement sensor. Background Art

[0002] In recent years, with the vigorous development of the manufacturing industry, the demand for high-precision large-scale manufacturing equipment has been increasing, and correspondingly, higher requirements have been placed on high-precision and large-range absolute linear displacement measurement technology. It is necessary to have a measuring range of several meters and high precision at the same time, and to achieve absolute positioning within a large range without measurement cumulative errors.

[0003] As one of many absolute displacement sensors, the electromagnetic absolute time-grating linear displacement sensor has the function of not losing the zero point when the power is off, and can achieve high-precision measurement and absolute positioning. It has been more and more widely used in the field of precision displacement measurement. However, the movable scale substrate of the current electromagnetic absolute time-grating linear displacement sensor cannot completely cover the coil on the fixed scale substrate, resulting in the coupling of the coil on the fixed scale substrate with various electromagnetic waves in the air, generating high-order harmonic interference, and it is difficult to realize the manufacturing of a single-section large-range sensor substrate due to the limitation of processing technology. Summary of the invention

[0004] The purpose of the present invention is to provide a spliced ​​absolute time-grating linear displacement sensor to reduce the interference of various electromagnetic waves in the air and realize a large-range absolute linear displacement measurement with a measurement range of several meters or even tens of meters.

[0005] The spliced ​​absolute time-grating linear displacement sensor of the present invention comprises a fixed scale and a moving scale which is parallel to the fixed scale and has a gap therebetween. The fixed scale comprises a fixed scale substrate, and the moving scale comprises a moving scale substrate and a sensing unit arranged on the moving scale substrate. The X direction is set as the measuring direction, the direction parallel to the fixed scale substrate and perpendicular to the X direction is the Y direction, and the direction perpendicular to the fixed scale substrate is the Z direction.

[0006] A rough machine coupling unit and a fine machine coupling unit are provided on the fixed-length substrate. The rough machine coupling unit is composed of M independent rough machine coupling coils arranged in a row at equal intervals along the X direction. The rough machine coupling coil is in a planar square spiral shape and the starting end is connected to the ending end. The fine machine coupling unit is composed of N independent fine machine coupling coils arranged in another row at equal intervals along the X direction. The fine machine coupling coil is in a planar square spiral shape and the starting end is connected to the ending end. The starting position of the fine machine coupling unit is aligned with the starting position of the rough machine coupling unit in the Y direction (that is, the starting position of the first rough machine coupling coil is aligned with the starting position of the first fine machine coupling coil in the Y direction). Among them, N*W2=M*W1, W1 represents the pole pitch of the rough machine coupling unit, W2 represents the pole pitch of the fine machine coupling unit, M and N are mutually prime, and M<N, D1 represents the distance between the starting position of the precision machining coupling unit (i.e., the left end of the outermost turn of the first precision machining coupling coil) and the left edge of the fixed-length substrate in the X direction, and D2 represents the distance between the ending position of the precision machining coupling unit (i.e., the right end of the outermost turn of the Nth precision machining coupling coil) and the right edge of the fixed-length substrate in the X direction.

[0007] There are S (S≥2) fixed lengths, and the S fixed lengths are spliced ​​head to tail in sequence along the X direction to form a fixed length group.

[0008] The movable ruler base is also provided with an excitation unit, which is composed of a positively wound planar rectangular spiral coil and a reversely wound planar rectangular spiral coil aligned in the Y direction and connected in series. The induction unit includes a rough machine induction unit located in the reversely wound planar rectangular spiral coil and facing the rough machine coupling unit, and a fine machine induction unit located in the positively wound planar rectangular spiral coil and facing the fine machine coupling unit.

[0009] During operation, the sensor is reset, the movable ruler moves relative to the fixed ruler group, an excitation signal (cosine excitation signal or sine excitation signal) is introduced into the excitation unit to generate an alternating air gap magnetic field, and the rough machine coupling unit and the fine machine coupling unit generate an alternating magnetic field under the action of the alternating air gap magnetic field (the alternating magnetic field is opposite to the alternating air gap magnetic field generated by the excitation unit), the rough machine induction unit couples with the alternating magnetic field and outputs a rough machine induction signal, the fine machine induction unit couples with the alternating magnetic field and outputs a fine machine induction signal, the rough machine induction signal and the fine machine induction signal are processed, and the absolute linear displacement value of the movable ruler relative to the fixed ruler is obtained by solution.

[0010] Preferably, the rough machine induction unit comprises the same structure, mutually insulated and the starting ends are staggered along the X direction. The first induction coil of the roughing machine and the second induction coil of the roughing machine; the fine machine induction unit includes the same structure, insulated from each other and the starting ends staggered along the X direction The first induction coil of the fine machine and the second induction coil of the fine machine, the first induction coil of the rough machine, the second induction coil of the rough machine, the first induction coil of the fine machine and the second induction coil of the fine machine are all formed by connecting the wire segments arranged in two adjacent layers through vias.

[0011] Preferably, the winding trajectory of the first induction coil of the roughing machine is a first sine curve and a second sine curve with the same starting position, amplitude A, period W1, number of periods Q, and phase difference of 180°; The second conductor segment wound by the first sinusoidal curve portion in the interval is located on the E wiring layer, and the first induction coil is along the The first conductor segment wound by the first sinusoidal curve portion in the interval and the The third wire segment wound by the first sinusoidal curve part in the interval is located on the F wiring layer; The fifth conductor segment wound by the second sinusoidal curve portion in the interval is located on the F wiring layer, and the first induction coil is along the The fourth conductor segment wound by the second sinusoidal curve portion within the interval and along The sixth wire segment wound around the second sinusoidal curve portion within the interval is located on the E wiring layer, the starting end of the 1st first wire segment is connected to the starting end of the 1st fourth wire segment through a via, the terminating end of the Qth third wire segment and the terminating end of the Qth sixth wire segment are led as the induction signal output port of the first induction coil of the coarse machine, forming a differential structure; wherein j1 takes all integers from 0 to Q-1 in sequence, Q≥2, and the E wiring layer is adjacent to the F wiring layer.

[0012] Since the structure of the second induction coil of the roughing machine is the same as that of the first induction coil of the roughing machine, the starting end is staggered along the X direction when arranged. Therefore, the second induction coil of the roughing machine also has a first wire segment, a second wire segment, a third wire segment, a fourth wire segment, a fifth wire segment, and a sixth wire segment.

[0013] Preferably, the winding trajectory of the first induction coil of the precision machine is a third sine curve and a fourth sine curve with the same starting position, amplitude A, period W2, number of periods P, and phase difference of 180°; The eighth conductor segment wound by the third sinusoidal curve in the interval is located on the E wiring layer, and the first induction coil of the precision machine is along the The seventh conductor segment wound by the third sinusoidal curve portion within the interval and along The ninth wire segment wound by the third sinusoidal curve part in the interval is located on the F wiring layer; the first induction coil of the precision machine is along the The eleventh conductor segment wound by the fourth sinusoidal curve in the interval is located on the F wiring layer, and the first induction coil of the precision machine is along the The fourth sine curve portion within the interval is wound with the tenth conductor segment and along The twelfth wire segment wound around the fourth sinusoidal curve portion within the interval is located on the E wiring layer, the starting end of the first seventh wire segment is connected to the starting end of the first tenth wire segment through a via, and the terminating end of the Pth ninth wire segment and the terminating end of the Pth twelfth wire segment are led as the induction signal output port of the first induction coil of the precision machine, forming a differential structure; wherein j2 takes all integers from 0 to P-1 in turn, and P≥2.

[0014] Since the structure of the second induction coil of the precision machine is the same as that of the first induction coil of the precision machine, the starting end is staggered along the X direction when arranged. Therefore, the second induction coil of the precision machine also has a seventh wire segment, an eighth wire segment, a ninth wire segment, a tenth wire segment, an eleventh wire segment, and a twelfth wire segment.

[0015] Preferably, P, Q, M, and N satisfy: Roundup() represents a round-up function, which can ensure the strength of the sensing signal without sacrificing the measurement range.

[0016] Preferably, the length of the outermost turn of the coarse coupling coil in the X direction is equal to The width in the Y direction is L1, and 2A≤L1<L4; the length of the outermost turn of the precision machine coupling coil in the X direction is equal to The width in the Y direction is L2, and 2A≤L2<L4; the innermost turn of the forward-winding planar rectangular spiral coil and the innermost turn of the reverse-winding planar rectangular spiral coil are both L3 in length in the X direction and L4 in width in the Y direction, and L3>max(Q*W1,P*W2), L4>2A, and max() represents the maximum value function.

[0017] Preferably, the rough machine coupling coil and the fine machine coupling coil have two winding methods: the first method is that the rough machine coupling coil is wound counterclockwise from inside to outside into a planar square spiral shape, and the fine machine coupling coil is wound counterclockwise from inside to outside into a planar square spiral shape. The second method is that the rough machine coupling coil is wound clockwise from outside to inside into a planar square spiral shape, and the fine machine coupling coil is wound clockwise from outside to inside into a planar square spiral shape.

[0018] Preferably, there are two winding methods for the forward-wound planar rectangular spiral coil and the reverse-wound planar rectangular spiral coil: the first method is that the forward-wound planar rectangular spiral coil is wound counterclockwise from the outside to the inside, and the reverse-wound planar rectangular spiral coil is wound clockwise from the inside to the outside, the starting end of the forward-wound planar rectangular spiral coil is connected to the ending end of the reverse-wound planar rectangular spiral coil, and the leading wires of the ending end of the forward-wound planar rectangular spiral coil and the starting end of the reverse-wound planar rectangular spiral coil serve as an excitation signal input port. The second method is that the forward-wound planar rectangular spiral coil is wound clockwise from the inside to the outside, and the reverse-wound planar rectangular spiral coil is wound counterclockwise from the outside to the inside, the ending end of the forward-wound planar rectangular spiral coil is connected to the starting end of the reverse-wound planar rectangular spiral coil, and the leading wires of the starting end of the forward-wound planar rectangular spiral coil and the ending end of the reverse-wound planar rectangular spiral coil serve as an excitation signal input port.

[0019] Preferably, the method of processing the roughing machine sensing signal and the fine machine sensing signal to calculate the absolute linear displacement value of the movable ruler relative to the fixed ruler includes:

[0020] The code of the displacement between the starting position of the precision machining coupling unit on the i-th fixed length and the starting position of the precision machining coupling unit on the i+1-th fixed length is set to i, i takes all integers from 1 to S-1 in sequence, and the code of the displacement between the starting position and the ending position of the precision machining coupling unit on the S-th fixed length is set to S.

[0021] Process the rough machine induction signal to obtain the phase difference Process the precision machine sensing signal to obtain the phase difference

[0022] Phase Difference Calculate and get the current roughing machine incremental displacement Δx′ t , for the phase difference Convert and get the current precision machine incremental displacement Δx t .

[0023] Using the current roughing incremental displacement Δx′ t 、Current precision machine incremental displacement Δx t Perform pole-to-pole positioning to obtain the pole-to-pole number V of the precision machine coupling unit that the moving ruler passes on the current fixed length.

[0024] Using the current roughing incremental displacement Δx′ t 、Current precision machine incremental displacement Δx t , calculate the code K corresponding to the position of the starting end of the current precision machine induction unit (that is, the leftmost end of the first precision machine induction coil), where 1≤K≤S.

[0025] Using the formula: x abs =(K-1)*N*W2+V*W2+Δx t , calculate the absolute linear displacement value x of the movable ruler relative to the fixed ruler group abs .

[0026] Preferably, the current roughing incremental displacement Δx′ is used t 、Current precision machine incremental displacement Δx t , the method of calculating the code K corresponding to the starting position of the current precision machine sensing unit is:

[0027] If the current displacement difference Δx″ t In the interval [-6, +6], and the last displacement difference Δx″ t-1 In the interval [-6+G N , 6+G N ], the code K is accumulated by 1 (ie K=K+1).

[0028] If the current displacement difference Δx″ t In the interval [-6+G N , 6+G N], and the last displacement difference Δx″ t-1 In the interval [-6, +6], the code K is decremented by 1 (ie, K=K-1).

[0029] Among them, the initial value of K is equal to 1; when Δx′ t ≥Δx t -6, Δx″ t =Δx′ t -Δx t ; when Δx′ t <Δx t -6, Δx″ t =W1+Δx′ t -Δx t ; when Δx′ t-1 ≥Δx t-1 -6, Δx" t-1 =Δx′ t-1 -Δx t -1; when Δx′ t-1 <Δx t-1 -6, Δx′ t-1 =W1+Δx′ t-1 -Δx t-1 ; Δx′ t-1 Indicates the incremental displacement of the last roughing, Δx t-1 Indicates the last precision machine incremental displacement, 6 indicates the preset error limit, G N It represents the distance in the X direction between the left end of the outermost turn of the Mth rough machine coupling coil and the left end of the outermost turn of the Nth fine machine coupling coil, 6, G N All are known parameters.

[0030] Preferably, the rough machine sensing signal is processed to obtain the phase difference The method is:

[0031] The coarse machine induction signal V1 output by the first induction coil of the coarse machine is filtered by the first bandpass filter and amplified by the first amplifier circuit to obtain the first standing wave signal E1; the coarse machine induction signal V2 output by the second induction coil of the coarse machine is filtered by the second bandpass filter and amplified by the second amplifier circuit to obtain the second standing wave signal E2.

[0032] The first standing wave signal E1 is multiplied by the modulation signal I1, and then filtered by the first low-pass filter and amplified by the fifth amplifier circuit to obtain the first electrical signal U1; the second standing wave signal E2 is multiplied by the modulation signal I1, and then filtered by the second low-pass filter and amplified by the sixth amplifier circuit to obtain the second electrical signal U2.

[0033] Divide the second electrical signal U2 by the first electrical signal U1, and calculate the inverse tangent of the division result to obtain the phase difference

[0034] Preferably, the precision machine sensing signal is processed to obtain the phase difference The method is:

[0035] The precision machining induction signal V3 output by the first precision machining induction coil is filtered by the third bandpass filter and amplified by the third amplifier circuit to obtain the third standing wave signal E3; the precision machining induction signal V4 output by the second precision machining induction coil is filtered by the fourth bandpass filter and amplified by the fourth amplifier circuit to obtain the fourth standing wave signal E4.

[0036] The third standing wave signal E3 is multiplied by the modulation signal I1, and then filtered by the third low-pass filter and amplified by the seventh amplifier circuit to obtain the third electrical signal U3; the fourth standing wave signal E4 is multiplied by the modulation signal I1, and then filtered by the fourth low-pass filter and amplified by the eighth amplifier circuit to obtain the fourth electrical signal U4.

[0037] The fourth electrical signal U4 is divided by the third electrical signal U3, and the inverse tangent of the division result is calculated to obtain the phase difference

[0038] Compared with the prior art, the present invention has the following effects:

[0039] (1) The coarse-machine coupling unit is composed of M mutually independent coarse-machine coupling coils, and the fine-machine coupling unit is composed of N mutually independent fine-machine coupling coils. The coupling of the alternating magnetic field is only within the range of the forward-winding planar rectangular spiral coil and the reverse-winding planar rectangular spiral coil, which reduces the high-order harmonic interference caused by the coupling of the coils on the sensor that are not covered by the passive scale substrate and various electromagnetic waves in the air, thereby improving the measurement accuracy of the sensor.

[0040] (2) S fixed-length scales are spliced ​​into a fixed-length scale group, and combined with a time-grating signal processing circuit to achieve a large-scale absolute linear displacement measurement, breaking the limitation of traditional scale manufacturing process on increasing the measuring range and having a wide range of application scenarios.

[0041] (3) Both the excitation signal and the sensing signal are processed on the moving scale side, which realizes the passive design of the fixed scale and simplifies the sensor structure.

[0042] (4) The excitation unit is composed of a forward-winding planar rectangular spiral coil and a reverse-winding planar rectangular spiral coil connected in series, which enhances the intensity of the sensing signal and improves the signal-to-noise ratio of the sensor.

[0043] (5) The differential structure of the first induction coil of the roughing machine makes the induced electromotive force generated by the part of the first induction coil of the roughing machine coupled to the alternating air gap magnetic field wound along the first sine curve offset the induced electromotive force generated by the part of the first induction coil of the roughing machine coupled to the alternating air gap magnetic field wound along the second sine curve, and the first induction coil of the roughing machine is only affected by the coupling unit of the roughing machine. The differential structure of the second induction coil of the roughing machine makes the induced electromotive force generated by the part of the second induction coil of the roughing machine coupled to the alternating air gap magnetic field wound along the first sine curve offset the induced electromotive force generated by the part of the second induction coil of the roughing machine coupled to the alternating air gap magnetic field wound along the second sine curve, and the second induction coil of the roughing machine is only affected by the coupling unit of the roughing machine. The differential structure of the first induction coil of the fine machine makes the induced electromotive force generated by the part of the first induction coil of the fine machine coupled to the alternating air gap magnetic field wound along the third sine curve offset the induced electromotive force generated by the part of the first induction coil of the fine machine coupled to the alternating air gap magnetic field wound along the fourth sine curve, and the first induction coil of the fine machine is only affected by the coupling unit of the fine machine. The differential structure of the second induction coil of the precision machine makes the induced electromotive force generated by the part of the second induction coil of the precision machine wound along the third sinusoidal curve coupled with the alternating air gap magnetic field offset the induced electromotive force generated by the part of the second induction coil of the precision machine wound along the fourth sinusoidal curve coupled with the alternating air gap magnetic field. The second induction coil of the precision machine is only affected by the precision machine coupling unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the structure of the movable ruler and the fixed ruler group in the embodiment of the present invention.

[0045] Figure 2 It is a schematic diagram of the structure of the fixed length in the embodiment of the present invention.

[0046] Figure 3 Schematic diagram of the structure of the sizing group in the embodiment of the present invention.

[0047] Figure 4 It is a schematic diagram of the structures of the excitation unit, the rough machining sensing unit, and the fine machining sensing unit in an embodiment of the present invention.

[0048] Figure 5 Schematic diagram of the structure of the rough machine induction unit in an embodiment of the present invention.

[0049] Figure 6 Schematic diagram of the structure of the precision machine sensing unit in an embodiment of the present invention.

[0050] Figure 7 4 is a block diagram of the signal processing principle in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] like Figures 1 to 7As shown, the spliced ​​absolute time-grid linear displacement sensor in the embodiment of the present invention includes S fixed rulers and a movable ruler that is parallel to the fixed ruler and has a gap (for example, 0.4 mm). The X direction is set as the measuring direction, the direction parallel to the fixed ruler and perpendicular to the X direction is the Y direction, and the direction perpendicular to the fixed ruler is the Z direction. The S fixed rulers are spliced ​​head to tail in the X direction to form a fixed ruler group; the S fixed rulers are numbered as fixed ruler No. 1, fixed ruler No. 2, ..., fixed ruler No. S.

[0052] like Figures 1 to 4 As shown, each fixed length includes a fixed length substrate 1 (using insulating material) and a rough machine coupling unit 3 and a fine machine coupling unit 4 arranged on the upper surface of the fixed length substrate 1. The rough machine coupling unit 3 is composed of M independent rough machine coupling coils 31 arranged in a row at equal intervals along the X direction. The rough machine coupling coil 31 is in a planar square spiral shape and the starting end and the ending end are connected by a wire through a via. The fine machine coupling unit 4 is composed of N independent fine machine coupling coils 41 arranged in another row at equal intervals along the X direction. The fine machine coupling coil 41 is in a planar square spiral shape and the starting end and the ending end are connected by a wire through a via. The starting position of the fine machine coupling unit 4 is aligned with the starting position of the rough machine coupling unit 3 in the Y direction (that is, the starting position of the first rough machine coupling coil 31 is aligned with the starting position of the first fine machine coupling coil 41 in the Y direction); wherein, N*W2=M*W1, W1 represents the pole pitch of the rough machine coupling unit, W2 represents the pole pitch of the fine machine coupling unit, M and N are mutually prime, and M<N, D1 represents the distance in the X direction between the starting position of the precision machine coupling unit 4 (i.e., the left end of the outermost turn of the first precision machine coupling coil) and the left edge of the fixed-length substrate 1, and D2 represents the distance in the X direction between the ending position of the precision machine coupling unit 4 (i.e., the right end of the outermost turn of the Nth precision machine coupling coil) and the right edge of the fixed-length substrate 1. As an example, M=7, N=20.

[0053] The length of the outermost turn of the coarse coupling coil 31 in the X direction is equal to The width in the Y direction is L1, and 2A≤L1<L4. The length of the outermost turn of the precision coupling coil 41 in the X direction is equal to The width in the Y direction is L2, and 2A≤L2<L4. As an example, L1=L2=2A.

[0054] In some embodiments, the rough machine coupling coil 31 is wound counterclockwise from inside to outside into a planar square spiral shape, and the fine machine coupling coil 41 is wound counterclockwise from inside to outside into a planar square spiral shape.

[0055] In some embodiments, the rough machine coupling coil 31 is wound clockwise from the outside to the inside into a planar square spiral shape, and the fine machine coupling coil 41 is wound clockwise from the outside to the inside into a planar square spiral shape.

[0056] like Figure 1 , Figures 4 to 6 As shown, the moving ruler includes a moving ruler substrate 2 (using an insulating material) and an excitation unit and an induction unit arranged on the lower surface of the moving ruler substrate 2. The excitation unit is composed of a positively wound planar rectangular spiral coil 71 and a reversely wound planar rectangular spiral coil 72 aligned in the Y direction and connected in series. The induction unit includes a roughing induction unit 5 and a fine-machine induction unit 6. The roughing induction unit 5 is located in the reversely wound planar rectangular spiral coil 72 and directly faces the roughing coupling unit 3. The fine-machine induction unit 6 is located in the positively wound planar rectangular spiral coil 71 and directly faces the fine-machine coupling unit 4.

[0057] like Figure 5 As shown, the rough machine induction unit 5 includes the same structure, mutually insulated and the starting ends are staggered along the X direction. The first induction coil 51 and the second induction coil 52 of the rough machine.

[0058] The winding trajectory of the first induction coil 51 of the roughing machine is a first sine curve and a second sine curve with the same starting position, amplitude A, period W1, number of periods Q, and phase difference of 180°. The second wire segments 512 (a total of Q wires) wound around the first sinusoidal curve in the interval are located on the E wiring layer, and the first induction coil 51 is connected along the The first conductor segment 511 (a total of Q conductor segments) wound around the first sinusoidal curve in the interval and along The third wire segment 513 (a total of Q wires) wound around the first sinusoidal curve in the interval is located on the F wiring layer, and the first wire segment 511 and the second wire segment 512 are connected at The corresponding positions (i.e., the peaks of the first sine curve) are connected through vias, and the second wire segment 512 and the third wire segment 513 are connected at The corresponding position (i.e., the trough of the first sine curve) is connected through a via. The fifth wire segment 515 (a total of Q wires) wound around the second sinusoidal curve in the interval is located on the F wiring layer, and the first induction coil 51 is connected along the The fourth conductor segment 514 (a total of Q conductor segments) wound around the second sinusoidal curve portion within the interval and along The sixth wire segment 516 (a total of Q wires) wound around the second sinusoidal curve in the interval is located on the E wiring layer, and the fourth wire segment 514 and the fifth wire segment 515 are located on the E wiring layer. The corresponding positions (i.e., the trough of the second sine curve) are connected through vias, and the fifth wire segment 515 and the sixth wire segment 516 are connected at The corresponding positions (i.e., the peaks of the second sine curve) are connected through vias, the starting end of the first first wire segment 511 and the starting end of the first fourth wire segment 514 along the positive direction of X are connected through vias, and the terminal end of the Qth third wire segment 513 and the terminal end of the Qth sixth wire segment 516 are used as the induction signal output port of the first induction coil 51 of the rough machine. Wherein, j1 takes all integers from 0 to Q-1 in sequence, Q≥2, the E wiring layer is adjacent to the F wiring layer, and both are under the moving ruler substrate 2. As an example, Q=2.

[0059] Since the structure of the second induction coil 52 of the roughing machine is the same as that of the first induction coil 51 of the roughing machine, the starting ends are staggered along the X direction when arranged. Therefore, the second induction coil 52 of the roughing machine also has a first wire segment, a second wire segment, a third wire segment, a fourth wire segment, a fifth wire segment, and a sixth wire segment.

[0060] like Figure 6 As shown, the precision machine induction unit 6 includes the same structure, mutually insulated and the starting ends are staggered along the X direction. The first induction coil 61 of the fine machine and the second induction coil 62 of the fine machine are provided. The starting end of the first induction coil 61 of the fine machine is aligned with the starting end of the first induction coil 51 of the rough machine along the Y direction.

[0061] The winding trajectory of the first induction coil 61 of the precision machine is the third sine curve and the fourth sine curve with the same starting position, amplitude A, period W2, number of periods P, and phase difference of 180°. The eighth wire segment 612 (a total of P wires) wound around the third sinusoidal curve in the interval is located on the E wiring layer, and the first induction coil 61 of the precision machine is along the The seventh conductor segment 611 (a total of P conductor segments) wound around the third sinusoidal curve in the interval and along The ninth wire segment 613 (a total of P wires) wound around the third sinusoidal curve in the interval is located on the F wiring layer, and the seventh wire segment 611 and the eighth wire segment 612 are located on the F wiring layer. The corresponding positions (i.e., the peaks of the third sinusoidal curve) are connected through vias, and the eighth wire segment 612 and the ninth wire segment 613 are connected at The corresponding position (i.e., the trough of the third sine curve) is connected through a via. The eleventh wire segment 615 (a total of P wires) wound around the fourth sinusoidal curve in the interval is located on the F wiring layer, and the first induction coil 61 of the precision machine is along the The tenth conductor segment 614 (a total of P conductor segments) wound around the fourth sinusoidal curve portion within the interval and along The twelfth conductor segment 616 (a total of P conductor segments) wound around the fourth sinusoidal curve in the interval is located on the E wiring layer, and the tenth conductor segment 614 and the eleventh conductor segment 615 are located on the E wiring layer. The corresponding positions (i.e., the trough of the fourth sine curve) are connected through vias, and the eleventh wire segment 615 and the twelfth wire segment 616 are connected at The corresponding position (i.e., the peak of the fourth sine curve) is connected through a via hole, the starting end of the first seventh wire segment 611 and the starting end of the first tenth wire segment 614 along the positive direction of X are connected through a via hole, and the terminal end of the Pth ninth wire segment 613 and the terminal end of the Pth twelfth wire segment 616 are connected as the induction signal output port of the precision machine first induction coil 61; wherein j2 takes all integers from 0 to P-1 in sequence, and P≥2. In some embodiments, Roundup() means rounding up. As an example, P=6.

[0062] Since the structure of the second induction coil 62 of the precision machine is the same as that of the first induction coil 61 of the precision machine, the starting end is staggered along the X direction when arranged. Therefore, the precision machine second induction coil 62 also has a seventh wire segment, an eighth wire segment, a ninth wire segment, a tenth wire segment, an eleventh wire segment, and a twelfth wire segment.

[0063] The innermost turns of the forward-winding planar rectangular spiral coil 71 and the reverse-winding planar rectangular spiral coil 72 have a length of L3 in the X direction and a width of L4 in the Y direction, and L3>max(Q*W1,P*W2), L4>2A, and max() represents the maximum value function.

[0064] In some embodiments, the forward-wound planar rectangular spiral coil 71 is wound counterclockwise from outside to inside, and the reverse-wound planar rectangular spiral coil 72 is wound clockwise from inside to outside. The starting end of the forward-wound planar rectangular spiral coil 71 is connected to the ending end of the reverse-wound planar rectangular spiral coil 72, and the ending end of the forward-wound planar rectangular spiral coil 71 and the starting end of the reverse-wound planar rectangular spiral coil 72 are led as excitation signal input ports.

[0065] In some embodiments, the forward-wound planar rectangular spiral coil 71 is wound clockwise from inside to outside, and the reverse-wound planar rectangular spiral coil 72 is wound counterclockwise from outside to inside, the terminal end of the forward-wound planar rectangular spiral coil 71 is connected to the starting end of the reverse-wound planar rectangular spiral coil 72, and the starting end of the forward-wound planar rectangular spiral coil 71 and the terminal end lead of the reverse-wound planar rectangular spiral coil 72 serve as excitation signal input ports.

[0066] like Figure 7As shown, when working, the sensor is reset, the code K corresponding to the starting end position of the current precision machine sensing unit is 1 (that is, the initial value of K is 1), the movable ruler moves relative to the fixed ruler group, and the cosine excitation signal i is passed into the excitation unit c =A1cos(ω1t), the excitation unit generates an alternating air gap magnetic field, which changes periodically in the X direction. The coarse machine coupling unit 3 and the fine machine coupling unit 4 generate an alternating magnetic field under the action of the alternating air gap magnetic field generated by the excitation unit (the alternating magnetic field is opposite to the alternating air gap magnetic field generated by the excitation unit). The first induction coil 51 of the coarse machine is coupled with the alternating magnetic field to output a coarse machine induction signal V1; the second induction coil 52 of the coarse machine is coupled with the alternating magnetic field to output a coarse machine induction signal V2; the first induction coil 61 of the fine machine is coupled with the alternating magnetic field to output a fine machine induction signal V3; the second induction coil 62 of the fine machine is coupled with the alternating magnetic field to output a fine machine induction signal V4. Wherein, A1 is the amplitude of the cosine excitation signal, ω1 is the angular frequency of the cosine excitation signal, ω1=2πf1, and f1 represents the frequency of the cosine excitation signal. As an example, f1=4MHz.

[0067] The roughing machine sensing signal V1, roughing machine sensing signal V2, fine machine sensing signal V3, and fine machine sensing signal V4 are processed to calculate the absolute linear displacement value x of the movable ruler relative to the fixed ruler group. abs . Specifically include:

[0068] In the first step, the code of the displacement between the starting position of the precision machining coupling unit on the i-th fixed length and the starting position of the precision machining coupling unit on the i+1-th fixed length is set to i, i takes all integers from 1 to S-1 in sequence, and the code of the displacement between the starting position and the ending position of the precision machining coupling unit on the S-th fixed length is set to S.

[0069] In the second step, the rough machine induction signal V1 is filtered by the first bandpass filter and amplified by the first amplifier circuit to obtain the first standing wave signal The rough machine induction signal V2 is filtered by the second bandpass filter and amplified by the second amplifier circuit to obtain the second standing wave signal The precision machine sensing signal V3 is filtered by the third bandpass filter and amplified by the third amplifier circuit to obtain the third standing wave signal The precision machine sensing signal V4 is filtered by the fourth bandpass filter and amplified by the fourth amplifier circuit to obtain the fourth standing wave signal Among them, K1 is the amplitude of the rough machining sensing signal output by the rough machining sensing unit 5, and K2 is the amplitude of the fine machining sensing signal output by the fine machining sensing unit 6.

[0070] The third step is to multiply the first standing wave signal E1 by the modulation signal I1=cos(ω1t), and then the product is filtered by the first low-pass filter and amplified by the fifth amplifier circuit to obtain the first electrical signal The second standing wave signal E2 is multiplied by the modulation signal I1=cos(ω1t), and then the product is filtered by the second low-pass filter and amplified by the sixth amplifier circuit to obtain the second electrical signal The third standing wave signal E3 is multiplied by the modulation signal I1=cos(ω1t), and then the product is filtered by the third low-pass filter and amplified by the seventh amplifier circuit to obtain the third electrical signal The fourth standing wave signal E4 is multiplied by the modulation signal I1=cos(ω1t), and then the product is filtered by the fourth low-pass filter and amplified by the eighth amplifier circuit to obtain the fourth electrical signal

[0071] The fourth step is to divide the second electrical signal U2 by the first electrical signal U1, and calculate the inverse tangent of the division result to obtain the phase difference The fourth electrical signal U4 is divided by the third electrical signal U3, and the inverse tangent of the division result is calculated to obtain the phase difference Phase Difference After conversion, we can get the incremental displacement Δx′ of the roughing machine. t , for the phase difference Convert and get the precision machine incremental displacement Δx t .

[0072] Step 5: Use the roughing machine to incrementally shift Δx′ t , precision machining incremental displacement Δx t Perform pole-to-pole positioning to obtain the pole number V of the precision machine excitation unit 4 that the movable ruler passes on the current fixed length. Use the current roughing machine incremental displacement Δx′ t 、Current precision machine incremental displacement Δx t , calculate the code K corresponding to the starting end position of the current precision machine sensing unit; where 1≤K≤S.

[0073] The method for calculating the code K corresponding to the starting end position of the current precision machine sensing unit is:

[0074] If the current displacement difference Δx″ t In the interval [-6, +6], and the last displacement difference Δx″ t-1 In the interval [-6+G N , 6+G N ], the code K corresponding to the starting end position of the current precision machine sensing unit is accumulated by 1 (i.e. K=K+1). If the current displacement difference Δx″ t In the interval [-6+G N , 6+G N ], and the last displacement difference Δx" t-1In the interval [-6, +6], the code K corresponding to the starting position of the precision machine sensing unit is reduced by 1 (i.e. K = K-1). The initial value of K is 1; when Δx′ t ≥Δx t -6, Δx″ t =Δx′ t -Δx t ; when Δx′ t <Δx t -6, Δx″ t =W1+Δx′ t -Δx t ; when Δx′ t-1 ≥Δx t-1 -6, Δx" t-1 =Δx′ t-1 -Δx t-1 ; when Δx′ t-1 <Δx t-1 -6, Δx" t-1 =W1+Δx′ t-1 -Δx t -1; Δx′ t-1 Indicates the incremental displacement of the last roughing, Δx t-1 Indicates the last precision machine incremental displacement, 6 indicates the preset error limit, G N It represents the distance between the left end of the outermost turn of the Mth rough machine coupling coil 31 and the left end of the outermost turn of the Nth fine machine coupling coil 41 in the X direction. N are known parameters.

[0075] Step 6. Use the formula: x abs =(K-1)*N*W2+V*W2+Δx t , calculate the absolute linear displacement value x of the movable ruler relative to the fixed ruler group abs .

Claims

1. A spliced ​​absolute time-grid linear displacement sensor, comprising a fixed ruler and a movable ruler which is parallel to the fixed ruler and has a gap therebetween, the fixed ruler comprising a fixed ruler substrate (1), the movable ruler comprising a movable ruler substrate (2) and a sensing unit arranged on the movable ruler substrate, the X direction being the measuring direction, the direction parallel to the fixed ruler substrate and perpendicular to the X direction being the Y direction, and the direction perpendicular to the fixed ruler substrate being the Z direction; the characteristics are: The cut-to-length substrate (1) is provided with a roughing coupling unit (3) and a fine-machine coupling unit (4); the roughing coupling unit (3) is composed of M mutually independent roughing coupling coils (31) arranged in a row at equal intervals along the X direction, the roughing coupling coils (31) are in a planar square spiral shape, and the starting end is connected to the ending end; the fine-machine coupling unit (4) is composed of N mutually independent fine-machine coupling coils (41) arranged in another row at equal intervals along the X direction, the fine-machine coupling coils (41) are in a planar square spiral shape, and the starting end is connected to the ending end; the starting position of the fine-machine coupling unit (4) is aligned with the starting position of the roughing coupling unit (3) in the Y direction; wherein N*W2=M*W1, W1 represents the pole pitch of the roughing coupling unit, W2 represents the pole pitch of the fine-machine coupling unit, M and N are mutually prime, and M<N, D1 represents the distance between the starting position of the precision machine coupling unit (4) and the left edge of the cut-length base (1) in the X direction, and D2 represents the distance between the ending position of the precision machine coupling unit (4) and the right edge of the cut-length base (1) in the X direction; There are S fixed lengths, and the S fixed lengths are spliced ​​in sequence from head to tail along the X direction to form a fixed length group; The movable ruler base (2) is also provided with an excitation unit, which is composed of a positively wound planar rectangular spiral coil (71) and a reversely wound planar rectangular spiral coil (72) aligned in the Y direction and connected in series; the induction unit comprises a rough machine induction unit (5) located in the reversely wound planar rectangular spiral coil (72) and facing the rough machine coupling unit (3), and a fine machine induction unit (6) located in the positively wound planar rectangular spiral coil (71) and facing the fine machine coupling unit (4); During operation, the sensor is reset, the movable ruler moves relative to the fixed ruler group, an excitation signal is introduced into the excitation unit, an alternating air gap magnetic field is generated, the roughing machine coupling unit (3) and the fine machining coupling unit (4) generate an alternating magnetic field under the action of the alternating air gap magnetic field, the roughing machine sensing unit couples with the alternating magnetic field and outputs a roughing machine sensing signal, the fine machining sensing unit couples with the alternating magnetic field and outputs a fine machining sensing signal, the roughing machine sensing signal and the fine machining sensing signal are processed, and the absolute linear displacement value of the movable ruler relative to the fixed ruler is calculated.

2. The spliced ​​absolute time-grating linear displacement sensor according to claim 1 is characterized in that: The rough machine induction unit (5) comprises a plurality of induction units having the same structure, being insulated from each other and having their starting ends staggered along the X direction. The roughing machine first induction coil (51) and the roughing machine second induction coil (52) are respectively provided; the fine machining induction unit (6) comprises a first induction coil (51) having the same structure, being insulated from each other and having the starting ends staggered in the X direction. The first induction coil (61) of the fine machine and the second induction coil (62) of the fine machine, the first induction coil (51) of the rough machine, the second induction coil (52) of the rough machine, the first induction coil (61) of the fine machine, and the second induction coil (62) of the fine machine are all formed by connecting the wire segments arranged in two adjacent layers through vias.

3. The spliced ​​absolute time-grating linear displacement sensor according to claim 2 is characterized in that: The winding trajectory of the first induction coil (51) of the roughing machine is a first sine curve and a second sine curve with the same starting position, amplitude A, period W1, number of periods Q, and phase difference of 180°; the winding trajectory of the first induction coil (51) of the roughing machine is The second conductor segment (512) wound around the first sinusoidal curve portion within the interval is located on the E wiring layer, and the first induction coil (51) of the coarse machine is along the The first conductor segment (511) wound by the first sinusoidal curve portion within the interval and the The third conductor segment (513) wound by the first sinusoidal curve portion in the interval is located on the F wiring layer; the first induction coil (51) of the rough machine is along the The fifth conductor segment (515) wound around the second sinusoidal curve portion within the interval is located on the F wiring layer, and the first induction coil (51) of the coarse machine is along the The fourth conductor segment (514) wound by the second sinusoidal curve portion within the interval and along The sixth wire segment (516) wound around the second sinusoidal curve portion within the interval is located on the E wiring layer, the starting end of the first first wire segment (511) and the starting end of the first fourth wire segment (514) are connected through a via, and the terminal end of the Qth third wire segment (513) and the terminal end of the Qth sixth wire segment (516) are connected as the induction signal output port of the first induction coil (51) of the rough machine; wherein j1 takes all integers from 0 to Q-1 in sequence, Q≥2, and the E wiring layer is adjacent to the F wiring layer; The winding trajectory of the first precision machine induction coil (61) is a third sine curve and a fourth sine curve with the same starting position, amplitude A, period W2, number of periods P, and phase difference of 180°; the first precision machine induction coil (61) is along the The eighth conductor segment (612) wound around the third sinusoidal curve portion within the interval is located on the E wiring layer, and the first induction coil (61) of the precision machine is along the The seventh conductor segment (611) wound by the third sinusoidal curve portion within the interval and along The ninth conductor segment (613) wound around the third sinusoidal curve portion within the interval is located on the F wiring layer; the first induction coil (61) of the precision machine is along the The eleventh conductor segment (615) wound around the fourth sinusoidal curve portion within the interval is located on the F wiring layer, and the first induction coil (61) of the precision machine is along the The tenth conductor segment (614) wound by the fourth sinusoidal curve portion within the interval and along The twelfth wire segment (616) wound around the fourth sinusoidal curve portion within the interval is located on the E wiring layer, the starting end of the first seventh wire segment (611) and the starting end of the first tenth wire segment (614) are connected through a via, and the terminal end of the Pth ninth wire segment (613) and the terminal end of the Pth twelfth wire segment (616) are connected as the induction signal output port of the precision machine first induction coil (61); wherein j2 takes all integers from 0 to P-1 in sequence, and P≥2.

4. The spliced ​​absolute time-grating linear displacement sensor according to claim 3 is characterized in that: The P, Q, M, and N satisfy: Roundup() represents the rounding up function.

5. The spliced ​​absolute time-grating linear displacement sensor according to claim 3 is characterized in that: The length of the outermost turn of the rough machine coupling coil (31) in the X direction is equal to The width in the Y direction is L1, and 2A≤L1<L4; The length of the outermost turn of the precision machine coupling coil (41) in the X direction is equal to The width in the Y direction is L2, and 2A≤L2<L4; The innermost turns of the forward-winding planar rectangular spiral coil (71) and the innermost turns of the reverse-winding planar rectangular spiral coil (72) have a length of L3 in the X direction and a width of L4 in the Y direction, and L3>max(Q*W1,P*W2), L4>2A, and max() represents a maximum value function.

6. The spliced ​​absolute time-grating linear displacement sensor according to any one of claims 3 to 5, characterized in that: The rough machine coupling coil (31) is wound counterclockwise from inside to outside into a planar square spiral shape, and the fine machine coupling coil (41) is wound counterclockwise from inside to outside into a planar square spiral shape; Alternatively, the rough machine coupling coil (31) is wound clockwise from the outside to the inside into a planar square spiral shape, and the fine machine coupling coil (41) is wound clockwise from the outside to the inside into a planar square spiral shape.

7. The spliced ​​absolute time-grating linear displacement sensor according to any one of claims 3 to 5, characterized in that: The forward-winding planar rectangular spiral coil (71) is wound counterclockwise from outside to inside, and the reverse-winding planar rectangular spiral coil (72) is wound clockwise from inside to outside. The starting end of the forward-winding planar rectangular spiral coil (71) is connected to the ending end of the reverse-winding planar rectangular spiral coil (72). The leading wires of the ending end of the forward-winding planar rectangular spiral coil (71) and the starting end of the reverse-winding planar rectangular spiral coil (72) serve as excitation signal input ports. Alternatively, the forward-wound planar rectangular spiral coil (71) is wound clockwise from inside to outside, and the reverse-wound planar rectangular spiral coil (72) is wound counterclockwise from outside to inside, the terminal end of the forward-wound planar rectangular spiral coil (71) is connected to the starting end of the reverse-wound planar rectangular spiral coil (72), and the starting end of the forward-wound planar rectangular spiral coil (71) and the terminal end of the reverse-wound planar rectangular spiral coil (72) are connected as excitation signal input ports.

8. The spliced ​​absolute time-grating linear displacement sensor according to any one of claims 2 to 5, characterized in that: The methods for processing the roughing machine sensing signal and the fine machine sensing signal to calculate the absolute linear displacement value of the movable ruler relative to the fixed ruler include: The code of the displacement between the starting position of the precision machine coupling unit on the i-th fixed length and the starting position of the precision machine coupling unit on the i+1th fixed length is set to i, i takes all integers from 1 to S-1 in sequence, and the code of the displacement between the starting position and the ending position of the precision machine coupling unit on the S-th fixed length is set to S; Process the rough machine induction signal to obtain the phase difference Process the precision machine sensing signal to obtain the phase difference Phase Difference Calculate and get the current roughing machine incremental displacement Δx′ t , for the phase difference Convert and get the current precision machine incremental displacement Δx t ; Using the current roughing incremental displacement Δx′ t 、Current precision machine incremental displacement Δx t Performing pole-to-pole positioning to obtain the pole-to-pole number V of the precision machine coupling unit (4) that the movable ruler passes through on the current fixed length; Using the current roughing incremental displacement Δx′ t 、Current precision machine incremental displacement Δx t , calculate the code K corresponding to the position of the starting end of the precision machine sensing unit, where 1≤K≤S; Using the formula: x abs =(K-1)*N*W2+V*W2+Δx t , calculate the absolute linear displacement value x of the movable ruler relative to the fixed ruler group abs .

9. The spliced ​​absolute time-grating linear displacement sensor according to claim 8, characterized in that: Using the current roughing incremental displacement Δx′ t 、Current precision machine incremental displacement Δx t , the method of calculating the code K corresponding to the starting position of the current precision machine sensing unit is: If the current displacement difference Δx″ t In the interval [-δ, +δ], and the last displacement difference Δx″ t-1 In the interval [-δ+G N ,δ+G N ], the code K is accumulated by 1; If the current displacement difference Δx″ t In the interval [-δ+G N ,δ+G N ], and the last displacement difference Δx″ t-1 In the interval [-δ, +δ], the code K is decremented by 1; Among them, the initial value of K is equal to 1; when Δx′ t ≥Δx t -δ, Δx″ t =Δx′ t -Δx t ; when Δx′ t <Δx t -δ, Δx″ t =W1+Δx′ t -Δx t ; when Δx′ t-1 ≥Δx t-1 -δ, Δx″ t-1 =Δx′ t-1 -Δx t-1 ; when Δx′ t-1 <Δx t-1 -δ, Δx″ t-1 =W1+Δx′ t-1 -Δx t-1 ; Δx′ t-1 Indicates the incremental displacement of the last roughing, Δx t-1 represents the last precision machining incremental displacement, δ represents the preset error limit, G N Indicates the distance in the X direction between the left end of the outermost turn of the Mth rough machine coupling coil (31) and the left end of the outermost turn of the Nth fine machine coupling coil (41).

10. The spliced ​​absolute time-grating linear displacement sensor according to claim 9, characterized in that: Process the rough machine induction signal to obtain the phase difference The method is: A first standing wave signal E1 is obtained by filtering a coarse machine induction signal V1 outputted by a first induction coil (51) of the coarse machine through a first band pass filter and amplifying it by a first amplifier circuit; a second standing wave signal E2 is obtained by filtering a coarse machine induction signal V2 outputted by a second induction coil (52) of the coarse machine through a second band pass filter and amplifying it by a second amplifier circuit; The first standing wave signal E1 is multiplied by the modulation signal I1, and then filtered by the first low-pass filter and amplified by the fifth amplifier circuit to obtain the first electrical signal U1; the second standing wave signal E2 is multiplied by the modulation signal I1, and then filtered by the second low-pass filter and amplified by the sixth amplifier circuit to obtain the second electrical signal U2; Divide the second electrical signal U2 by the first electrical signal U1, and calculate the inverse tangent of the division result to obtain the phase difference Process the precision machine sensing signal to obtain the phase difference The method is: The precision machine induction signal V3 output by the precision machine first induction coil (61) is filtered by a third band pass filter and amplified by a third amplifier circuit to obtain a third standing wave signal E3; the precision machine induction signal V4 output by the precision machine second induction coil (62) is filtered by a fourth band pass filter and amplified by a fourth amplifier circuit to obtain a fourth standing wave signal E4; The third standing wave signal E3 is multiplied by the modulation signal I1, and then filtered by the third low-pass filter and amplified by the seventh amplifier circuit to obtain a third electrical signal U3; the fourth standing wave signal E4 is multiplied by the modulation signal I1, and then filtered by the fourth low-pass filter and amplified by the eighth amplifier circuit to obtain a fourth electrical signal U4; The fourth electrical signal U4 is divided by the third electrical signal U3, and the inverse tangent of the division result is calculated to obtain the phase difference

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